U.S. patent application number 12/612165 was filed with the patent office on 2011-05-05 for transducer device having strain relief coil housing.
Invention is credited to Aaron Harmon, Trent Hassell.
Application Number | 20110100703 12/612165 |
Document ID | / |
Family ID | 43919585 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110100703 |
Kind Code |
A1 |
Harmon; Aaron ; et
al. |
May 5, 2011 |
TRANSDUCER DEVICE HAVING STRAIN RELIEF COIL HOUSING
Abstract
A transducer device includes an annular housing having a base
wall adjoining a pair of annular side walls. The base and side
walls define an annular groove. An access port and at least one
strain relief opening are formed in the base wall. The at least one
strain relief opening is spaced apart from the access port. A
conductor is disposed in the annular groove.
Inventors: |
Harmon; Aaron; (Provo,
UT) ; Hassell; Trent; (Pleasant Grove, UT) |
Family ID: |
43919585 |
Appl. No.: |
12/612165 |
Filed: |
November 4, 2009 |
Current U.S.
Class: |
174/520 |
Current CPC
Class: |
E21B 47/13 20200501;
E21B 17/028 20130101 |
Class at
Publication: |
174/520 |
International
Class: |
H01R 13/46 20060101
H01R013/46 |
Claims
1. A transducer device, comprising: an annular housing having a
base wall adjoining a pair of annular side walls, the base and side
walls defining an annular groove, the base wall having an access
port and at least one strain relief opening formed therein, the at
least one strain relief opening being spaced apart from the access
port; and a conductor disposed in the annular groove.
2. The transducer device of claim 1, wherein the at least one
strain relief opening is a through-hole extending from an exterior
surface of the base wall to the annular groove.
3. The transducer device of claim 1, wherein the at least one
strain relief opening is a blind hole extending from an exterior
surface of the base wall partially into the base wall.
4. The transducer device of claim 1, wherein the at least one
strain relief opening is a slot formed in an exterior surface of
the base wall.
5. The transducer device of claim 4, wherein the slot is a
half-slot having a radial width less than a radial width of the
base wall.
6. The transducer device of claim 4, wherein the slot is a
full-slot having a radial width equal to a radial width of the base
wall.
7. The transducer device of claim 1, wherein a plurality of strain
relief openings are formed in the base wall.
8. The transducer device of claim 7, wherein the strain relief
openings and access port are uniformly spaced apart along the base
wall.
9. The transducer device of claim 1, wherein the access port
extends from the annular groove to an exterior surface of the base
wall.
10. The transducer device of claim 10, wherein the conductor
extends through the access port to an exterior of the annular
housing.
11. The transducer device of claim 1, wherein the annular housing
is adapted for mounting on a tubular.
12. A downhole tool, comprising: a tubular having a receptacle; and
a transducer device disposed in the receptacle, the transducer
device comprising: (i) an annular housing having a base wall
adjoining a pair of annular side walls, the base and side walls
defining an annular groove, the base wall having an access port and
at least one strain relief opening formed therein, the at least one
strain relief opening being spaced apart from the access port; and
(ii) a conductor disposed in the annular groove.
Description
TECHNICAL FIELD
[0001] The invention relates generally to borehole telemetry
systems. More specifically, the invention relates to transducer
devices for transmitting signals along a drill string.
BACKGROUND
[0002] In downhole drilling operations, downhole measuring tools
are used to gather information about geological formations, status
of downhole tools, and other downhole conditions. Such data is
useful to drilling operators, geologists, engineers, and other
personnel located at the surface. This data may be used to adjust
drilling parameters, such as drilling direction, penetration speed,
and the like, to effectively tap into an oil or gas bearing
reservoir. Data may be gathered at various points along the drill
string, such as from a bottom-hole assembly or from sensors
distributed along the drill string. Once gathered, apparatus and
methods are needed to rapidly and reliably transmit the data to the
surface. Traditionally, mud pulse telemetry has been used to
transmit data to the surface. However, mud pulse telemetry is
characterized by a very slow data transmission rate (typically in a
range of 1-6 bits/second) and is therefore inadequate for
transmitting large quantities of data in real time. Other telemetry
systems, such as wired pipe telemetry system and wireless telemetry
system, have been or are being developed to achieve a much higher
transmission rate than possible with the mud pulse telemetry
system.
[0003] Wired pipe telemetry systems using a combination of
electrical and magnetic principles to transmit data between a
downhole location and the surface are described in, for example,
U.S. Pat. Nos. 6,670,880, 6,992,554, and 6929493. U.S. Pat. No.
6,670,880, for example, discloses that such a system will transmit
data at a rate of least 100 bits/second and conceivably at a rate
as high as 1,000,000 bits/second. In these systems, inductive
transducers are provided at the ends of wired pipes. The inductive
transducers at the opposing ends of each wired pipe are electrical
connected by an electrical conductor running along the length of
the wired pipe. Data transmission involves transmitting an
electrical signal through an electrical conductor in a first wired
pipe, converting the electrical signal to a magnetic field upon
leaving the first wired pipe using an inductive transducer at an
end of the first wired pipe, and converting the magnetic field back
into an electrical signal using an inductive transducer at an end
of the second wired pipe. Several wired pipes are typically needed
for data transmission between the downhole location and the
surface.
[0004] For uninterrupted data transmission from the downhole
location to the surface, the transducer devices used in the wired
pipe telemetry system must be electrically and structurally
reliable. Several measures have been taken to ensure electrical
reliability of inductive transducers. U.S. Pat. No. 6,992,554, for
example, describes a robust data transmission element (i.e.,
inductive transducer) for transmitting information between downhole
components. In this patent, the data transmission element includes
a U-shaped annular housing. A U-shaped magnetically conducting,
electrically insulating (MCEI) element is arranged in the U-shaped
annular housing. An insulated conductor is located within the
U-shaped MCEI element. As current flows through the insulated
conductor, a magnetic flux or field is created around the insulated
conductor. The MCEI element contains the magnetic flux created by
the insulated conductor and prevents energy leakage into
surrounding materials. The annular housing is made of a hard
material that is electrically conductive, typically a metal.
Although not specifically discussed in this patent, there is a
through-hole in the annular housing as well as the MCEI element to
allow for insertion of an input lead to the insulated conductor.
Thus, a weak spot is inherently designed into the annular
housing.
[0005] U.S. Pat. No. 6,992,554 discloses that the annular housing
stretches as it is forced into the recess within the mating surface
of a downhole component. This stretching action provides a rebound
force to return the annular housing to its original position when
the force is removed. When the annular housing stretches, the area
surrounding the through-hole created in the annular housing for the
input lead would absorb more of the stretch than the rest of the
annular housing. As a result, strain induced in the annular housing
as a result of the stretching would concentrate around the
through-hole for the input lead. The material in this highly
strained region may exceed its elastic limit sooner than the
material in the remainder of the annular housing, causing the
annular housing and inductive transducer to fail structurally
prematurely. This disclosure discloses how to prevent or curb this
premature structural failure.
SUMMARY
[0006] In a first aspect, the present invention relates to a
transducer device comprising: an annular housing having a base wall
adjoining a pair of annular side walls, the base and side walls
defining an annular groove, the base wall having an access port and
at least one strain relief opening formed therein, the at least one
strain relief opening being spaced apart from the access port; and
a conductor disposed in the annular groove.
[0007] In certain embodiments of the first aspect of the present
invention, the at least one strain relief opening is a through-hole
extending from the exterior surface of the base wall to the annular
groove.
[0008] In certain embodiments of the first aspect of the present
invention, the at least one strain relief opening is a blind hole
extending from the exterior surface of the base wall partially into
the base wall.
[0009] In certain embodiments of the first aspect of the present
invention, the at least one strain relief opening is a slot formed
in the exterior surface of the base wall.
[0010] In certain embodiments of the first aspect of the present
invention, the slot is a half-slot having a radial width less than
a radial width of the base wall.
[0011] In certain embodiments of the first aspect of the present
invention, the slot is a full-slot having a radial width equal to a
radial width of the base wall.
[0012] In certain embodiments of the first aspect of the present
invention, a plurality of strain relief openings are formed in the
base wall.
[0013] In certain embodiments of the first aspect of the present
invention, the strain relief openings and access port are uniformly
spaced-apart along the base wall.
[0014] In certain embodiments of the first aspect of the present
invention, the access port extends from the annular groove to an
exterior surface of the base wall.
[0015] In certain embodiments of the first aspect of the present
invention, the conductor extends through the access port to an
exterior of the annular housing.
[0016] In certain embodiments of the first aspect of the present
invention, the annular housing is adapted for mounting on a
tubular.
[0017] In a second aspect, the present invention relates to a
downhole tool comprising: a tubular having a receptacle and a
transducer device according to the first aspect of the present
invention disposed in the receptacle.
BRIEF DESCRIPTION OF DRAWINGS
[0018] The following is a description of the figures in the
accompanying drawings. The figures are not necessarily to scale,
and certain features and certain views of the figures may be shown
exaggerated in scale or in schematic in the interest of clarity and
conciseness.
[0019] FIG. 1 is a perspective view of a transducer device.
[0020] FIG. 2 is a radial cross-section of the transducer device
including strain relief through-holes.
[0021] FIG. 3 is a perspective view of a transducer device.
[0022] FIG. 4 is a radial cross-section of a transducer device
including strain relief blind holes.
[0023] FIG. 5 is a side view of a transducer device including
strain relief full-slots.
[0024] FIG. 6 is a side view of a transducer device including
strain relief half-slots.
[0025] FIG. 7 shows the transducer of FIG. 1 mounted on a downhole
tool.
[0026] FIG. 8 is a radial cross-section of a transducer device
mounted in a recess of a downhole tool.
DETAILED DESCRIPTION
[0027] The present invention will now be described in detail, with
reference to the accompanying drawings. In this detailed
description, numerous specific details may be set forth in order to
provide a thorough understanding of the invention. However, it will
be apparent to one skilled in the art when the invention may be
practiced without some or all of these specific details. In other
instances, well-known features and/or process steps may not be
described in detail so as not to unnecessarily obscure the
invention. In addition, like or identical reference numerals may be
used to identify common or similar elements.
[0028] FIG. 1 shows a transducer device 1 according to certain
aspects of the present invention. The transducer device 1 has an
annular housing 3 made of an inner annular side wall 7, an outer
annular side wall 8, and a base wall 5 adjoining the side walls 7,
8. The annular housing 3 is made of a hard electrically conductive
material, typically a metal such as steel, titanium, chrome,
nickel, aluminum, iron, copper, tin, and lead. FIG. 2 shows that
the walls 5, 7, 8 define an annular groove 9. A coil assembly 11 is
disposed in the annular groove 9. The coil assembly 11 includes a
conductor 13 disposed and retained in an insert 21, where the
insert 21 is disposed and retained in the annular groove 9 of the
annular housing 3. The conductor 13 is an insulated conductor
including a conductor 29 surrounded by an electrically insulating
material 31. The conductor 13 may be, for example, a nickel- or
silver-plated, copper-clad, stainless-steel wire. Other types of
conductors are known in the art. The conductor 13 may have a
cross-section that is circular or has other shape, e.g.,
rectangular. In the coil assembly 11, as current flows through the
conductor 13, a magnetic flux or field is created around the
conductor 13. In FIG. 1, the conductor 13 extends through an access
port 15 formed in the base wall 5. The access port 15 is a
through-hole in that it extends through the thickness of the base
wall 5 in order to provide a path between the annular groove (9 in
FIG. 2) and the exterior surface 35 of the base wall 5. In FIG. 3,
an anti-rotation sleeve 39 is installed at the access port (15 in
FIG. 1). An insulating coating 32 may be applied on a portion of
the conductor 13. A seal stack 34 may be provided on a portion of
or above the insulating coating 32 to provide a seal between the
conductor 13 and a tool body (i.e., when the transducer device 1 is
mounted in a tool body).
[0029] In general, the coil assembly 11 may have any configuration
suitable for converting a magnetic field to an electrical field or
an electrical field to a magnetic field. Examples of suitable coil
assemblies are disclosed in, for example, U.S. Pat. Nos. 6,670,880,
6,992,554, and 6,929,493. The insert 21 may be configured to
perform functions such as containing magnetic flux created by the
conductor 13 within the annular housing 3 and transferring magnetic
current to another insert of another transducer device during a
data transmission operation using two oppositely-arranged
transducer devices. If the coil assembly 11 is similar to the ones
disclosed in U.S. Pat. No. 6,992,554, then the insert 21 would be a
U-shaped magnetically conducting electrically insulating (MCEI)
element as described in U.S. Pat. No. 6,992,554. In this case, the
insert 21 may be retained in the annular groove 3 via a polymer
layer 23 disposed between the walls 5, 7, 8 of the annular housing
3 and the insert 21. The conductor 13 may be retained in a pocket
25 provided by the insert 21 via a polymer layer 27 disposed in the
pocket 25 between the insert 21 and the conductor 13. In an
alternative example, the coil assembly 11 may have a structure
similar to the one disclosed in U.S. Pat. No. 6,929,493, where the
insert 21 would be made of a resilient material and fit snugly in
the annular groove 9, and the conductor 13 would fit snugly in a
pocket provided by the insert 21. In general, the annular housing 3
and the insert 21 may be provided with snap features such as
undercuts and recesses to assist in retaining the insert 21 in
place within the annular groove 9 of the annular housing 3.
[0030] Referring to FIG. 1 or 3, a plurality of openings 40 are
formed in the base wall 5. The openings 40 are for strain relief.
At the location of each of the strain relief openings 40 and the
access port 15, the base wall 5 has a reduced cross-sectional area.
If the strain relief openings 40 had not been formed in the base
wall 5 as illustrated in FIG. 1 or 3, strain induced in the annular
housing 3 will concentrate mostly at the reduced cross-sectional
area at the location of the access port 15, possibly resulting in
premature failure of the annular housing 3 as explained in the
background. However, with the provision of the strain relief
openings 40 in the base wall 5, strain induced in the annular
housing 3 (e.g., as a result of the annular housing 3 stretching)
will be distributed among the reduced cross-sectional areas at the
location of the strain relief openings 40 and the access port 15.
By sharing the strain burden, the strain relief openings 40 reduce
the amount of strain concentrated at the location of the access
port 15. Preliminary tests suggest that providing the strain relief
openings 40 in the base wall 5 can potentially increase the life
expectancy of the transducer device 1 by a minimum of 2,000% with
minimal impact on strength and rebound force of the annular housing
3.
[0031] Preferably, there are at least two strain relief openings 40
formed in the base wall 5 in addition to the access port 15. As
shown in FIG. 2, the strain relief openings 40 formed in the base
wall 5 may be through-holes, i.e., extending through the base wall
5, from the outer surface 35 of the base wall 5 to the annular
groove 9, as shown in FIG. 2. Alternatively, as shown in FIG. 4,
the strain relief openings 40 may be blind holes, i.e., extending
only partially into the base wall 5 (from the exterior surface 35
of the base wall 5). A mixture of through-hole and blind-hole
strain relief openings 40 may be formed in the base wall 5, as
shown in FIG. 1 or 3. Alternatively, only through-hole strain
relief openings 40 or blind-hole strain relief openings 40 may be
formed in the base wall 5. Alternatively, as shown in FIGS. 5 and
6, the strain relief openings 40 may be slots cut in the exterior
surface 35 of the base wall 5. In FIG. 5, the slots 40 are
full-slots in that they extend fully across the radial width of the
base wall 5. The radial width W of the base wall 5 is indicated in
FIG. 1. The radial width of a full-slot is equal to the radial
width W of the base wall 5. In FIG. 6, the slots 40 are half-slots
in that they extend partially across the width of the base wall 5.
The radial width of a half-slot is less than the radial width W of
the base wall 5. The half-slot may start from the side of the base
wall 5 adjacent to the outer annular side wall (8 in FIG. 1) or the
side of the base wall 5 adjacent to the inner annular side wall (7
in FIG. 1) to some point along the radial width W of the base wall
5. The wall of each of the strain relief openings 40 may be
straight or may be angled or chamfered. In FIGS. 1, 3, 5, and 6 the
strain relief openings 40 are spaced apart from the access port 15
and also from each other. Preferably, the strain relief openings 40
and access port 15 are uniformly spaced apart along the base wall 5
so that the strain induced in the annular housing 3 is uniformly
distributed along the base wall 5. The strain relief openings 40
may have any desired shape, e.g., circular, square, rectangular,
oval, rectangular with rounded corners, and square with rounded
corners. Preferably, the strain relief openings 40 do not have
sharp corners at the exterior surface 35 of the base wall 5 that
can act as stress concentrators.
[0032] FIG. 7 shows the transducer device 1 mounted on a downhole
tool 38. In FIG. 7, the downhole tool 28 is a tubular. The tubular
can be any tubular adapted for use in borehole operations, e.g.,
drill pipe, casing, metallic pipe, non-metallic pipe, wired pipe,
and non-wired pipe. In FIG. 8, the transducer device 1 is disposed
in a recess 36 of the downhole tool 38. The downhole tool 38 may
be, for example, a wired pipe, and the recess 36 may be formed in a
shoulder of the wired pipe. In FIG. 8, the annular housing 3 has an
angled surface 41, and the recess 36 has an angled surface 43 in
opposing relation to the angled surface 41 of the annular housing
3. The angled surface 41 of the annular housing 3 acts as a spring
against the angled surface 43 of the recess 36. As force is applied
to the transducer device 1 and the angled surface 41 presses down
on the angled surface 43, the annular housing 3 stretches. This
stretching action provides a rebound force to return the annular
housing 3 to its original position once the force is removed. The
stretching of the annular housing 3 will induce strain in the
annular housing 3. As explained above, the strain relief openings
40 in the base wall 5 of the annular housing 3 will distribute the
induced strain along the base wall 5 so that the annular housing 3
does not fail prematurely due to excess concentration of strain at
a single location (i.e., at access port 15 in FIG. 1) in the base
wall 5.
[0033] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *